/*
 * Copyright 2008-2011 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package net.conquiris.qs;

import java.io.IOException;

/**
 * Base class for QS tokens.
 * @author Andres Rodriguez
 */
public abstract class Token {
	/** Constructor. */
	Token() {
	}

	/**
	 * Writes the token to an appendable character stream.
	 * @param first Whether this token is the first token.
	 * @param qs Query service to use for name resolution.
	 * @param a Appendable to use.
	 */
	final void write(boolean first, QS qs, Appendable a) throws IOException {
		if (!first) {
			a.append(' ');
		}
		write(qs, a);
	}

	/**
	 * Internal writing method. Must no be called directly.
	 * @param qs Query service to use for name resolution.
	 * @param a Appendable to use.
	 */
	abstract void write(QS qs, Appendable a) throws IOException;

}
